1. Field of the Invention
The present invention relates to conveyor apparatus, and more particularly, to a diverting roller system comprising a roller transfer station disposed within a field of rollers and adapted for transfering an article carried thereon into a relatively angular direction.
2. History of the Prior Art
The prior art is replete with conveyor roller systems utilized for conveying articles such as luggage, parcels, cartons and package items. Such systems are utilized in warehouses, factories, and commercial distribution organizations such as the post office. For controlled routing and delivery of the articles being conveyed, it is frequently necessary to transfer them at an angle onto still another conveyor or roller system. The transfer, or diverting, is often selectively necessary as in conveyor systems used in routing articles onto intersecting conveyor lines in response to the designation of the particular article.
Numerous prior art designs have been utilized for angularly diverting articles conveyed upon a roller system. Prior mechanical devices for diverting have been shown to be unreliable, expensive to build and, in many instances, expensive to operate. Moreover, it has generally been difficult to implement a diverting system into an existing roller or conveyor system without extensive modification. Structural and functional considerations contribute to this difficulty. The primary functional aspect of a diverting system is the power drive of the diverting rollers. Because the articles being conveyed are often heavy, a "passive" diverting roller, that is one without an independent drive, will often simply become an impediment to further motion of the article upon the conveyor system. The capacity to move the article sideways at a fixed angle, which is often a right angle, requires the ability to turn the article upon its vertical axis and change the horizontal orientation so that one side can be turned to face a desired direction each time a transfer is made. This step generally requires a driving transfer roller in engagement with the article.
Power trains for diverting rollers have been constructed in a myriad of configurations. Drive chains, gears, and related transmission devices have, for example, been utilized. The mechanical complexity of such diverting stations is one contributing factor to the inherent unreliability and expense thereof. For these reasons, numerous inventive steps have been taken in the prior art to overcome certain of the aforesaid disadvantages. For example, U.S. Pat. No. 4,180,150 dated Dec. 25, 1979, was issued for a "Multi-Directional Transfer Device". The transfer station set forth therein includes at least three single, tilted wheels that are driveable and also steerable in a horizontal plane. The wheels are intended to impart the desired thrust vectors for horizontal, linear, and rotational movement of an article carried by the conveyor system. Steering is provided by a chain and sprocket mechanism while roller rotation is accomplished through a belt 22 and gear motor 23. Such mechanisms are useful in diverting articles upon the conveyor system but require independent drive means.
Other prior art transfer embodiments incorporate diverter mechanisms having live roller conveyors in which the diverter wheels are positively powered by the drive belt of the conveyor. One such apparatus is set forth in U.S. Pat. No. 3,138,238 issued June 23, 1964, for a "Powered Diverter". The apparatus set forth therein includes a simple diverter mechanism which may be installed on any standard conveyor line without substantial structural modifications and which incorporates a positive drive of the diverter roller. It is advantageous to incorporate a construction fully compatible with standard live roller conveyor systems which do not require extensive structural changes. As set forth in that U.S. Pat. No. 3,138,238, the diverter wheels are powered by the main conveyor belt itself with the same tangential velocity as the carrier roller of the main conveyor. This design aspect prevents slippage of the articles on the diverter wheels. Such features are important for assuring positive and accurate turning of the article so that it is transferred on to the intersecting conveyor in an exactly centered position. The positive belt drive of this prior art structure also eliminates the necessity for a separate transmission system since the diverting rollers are driven directly by the underlying belt.
Prior art belt driven roller systems often reduce the complexity and cost of the assembly and improve reliability by elimination of complex mechanical linkages. However, the problem of abnormal belt wear, abrasion, and frictional deterioration between the rollers and the belt is particularly a problem with diverter rollers. Because the diverter must orient its rolling surface at an angle relative to the belt, deleterious drag and wear is often imparted to the belt which reduces severely the system life and overall reliability. Belt drag and deterioration as well as positive drive requirements may thus be seen to be one underlying reason for incorporation of positive drive means such as belts, gear, and other transmission apparatus incorporated by the prior art. It would be an advantage, however, to provide a diverting mechanism incorporating the advantageous features of conveyor belt driven diverting rollers without the deleterious results and/or complex and costly mechanical assemblies generally found in prior art apparatus.
The method and apparatus of the present invention overcome the problems of the prior art by providing a diverting roller system incorporating an aligned drive roller and reciprocally mounted diverting roller. The diverting roller is designed for entry into and from the notional plane of conveyance while being positively driven from the underlying drive roller engaging the conveyor belt in axially aligned rotational engagement. The diverter roller of the present invention is angularly mounted relative to the belt drive powering roller which maintains its positive, aligned engagement with the conveyor belt. In this manner, the diverting roller may be selectively actuated for entry into the notional plane of conveyance for diverting articles passing therethrough.